1. Field of the Invention
The present invention generally relates to magnetic-tape devices, and particularly relates to a magnetic-tape device which writes data in and reads data from a magnetic-tape cartridge by attending to thread control.
2. Description of the Related Art
Conventionally used data recording devices include magnetic-tape devices, which use a magnetic-tape cartridge that can record data by utilizing a magnetic recording scheme. Such magnetic-tape devices are typically used for recording a large size of data.
FIG. 19 is an illustrative drawing showing a related-art magnetic-tape device including a magnetic-tape cartridge.
A magnetic-tape device 1 includes a magnetic-tape cartridge 2, a machine reel 3, a leader block 4, a threader motor 5, roller guides 6, cleaners 7, a head 8, a magnetic tape 9, and a threader pin 10.
The magnetic-tape cartridge 2 can be detached from the magnetic-tape device 1 for replacement.
In FIG. 19, the magnetic tape 9 of the magnetic-tape cartridge 2 is hooked around the roller guides 6 and the cleaners 7 to come in contact with the head 8, and the leader block 4 is placed in a threaded position, being positioned inside the machine reel 3. The leader block 4 is fixed to the threader pin 10, and is led out from the magnetic-tape cartridge 2 to be threaded under the control of the threader motor 5. In this condition, the head 8 records data in and reproduces data from the magnetic tape.
FIGS. 20A and 20B are illustrative drawings showing an example of a magnetic-tape cartridge of an old type.
FIG. 20A illustrates a front side of the magnetic-tape cartridge along with a leader-block portion 20xe2x80x2 which is used for fixing the leader block 4 to the threader pin 10. FIG. 20B illustrates a back side of the magnetic-tape cartridge where no slits are provided at portions 21xe2x80x2.
FIGS. 20C and 20D are illustrative drawings showing an example of a magnetic-tape cartridge.
FIGS. 20C and 20D show a magnetic-tape cartridge 2 of a new type having a magnetic tape of a standard length. FIG. 20C illustrates a front side of the magnetic-tape cartridge along with a leader-block portion 20 which is used for fixing the leader block 4 to the threader pin 10. FIG. 20D illustrates a back side of the magnetic-tape cartridge where cartridge identifying slits 21 are provided to indicate a difference of cartridge type.
FIGS. 21A and 21B are illustrative drawings showing an example of a magnetic-tape cartridge.
FIGS. 21A and 21B show a magnetic-tape cartridge 2 of a new type having a magnetic tape of a double length. FIG. 21A illustrates a front side of the magnetic-tape cartridge along with a leader-block portion 22 which is used for fixing the leader block 4 to the threader pin 10. FIG. 21B illustrates a back side of the magnetic-tape cartridge where cartridge identifying slits 23 are provided to indicate a difference of cartridge type.
Among those magnetic-tape cartridges illustrated above, those of the new type are identical to each other in the shape of part of the leader-block portion that comes in contact with the threader pin, but differ from each other in positions of the cartridge identifying slits. The magnetic-tape cartridge of the old type has the leader-block portion 20xe2x80x2 that is different from the leader-block portion 20 or 22 of the new-type magnetic-tape cartridge in terms of the shape of a portion that comes in contact with the threader pin, and does not have slits at the portions 21xe2x80x2.
FIG. 22 is an illustrative drawing showing the magnetic-tape cartridge 2.
In FIG. 22, the magnetic-tape cartridge 2 includes the magnetic tape 9 wrapped around a reel 24 and the leader block 4 attached to the beginning of the magnetic tape 9.
The leader-block portion 20, 20xe2x80x2, or 22 includes the leader block 4, which receives the threader pin 10 in a recess thereof. When the leader block 4 is fixed to the threader pin 10, the leader block 4 is taken out from the leader-block portion 20, 20xe2x80x2, or 22 to be threaded to the magnetic-tape device 1.
FIG. 23 is an illustrative drawing showing an example of the leader-block portion 20xe2x80x2 of the old magnetic-tape cartridge shown in FIGS. 20A and 20B.
In FIG. 23, a threader pin 100 connected to a tip of a threader arm 11 has a pin head 13 attached thereto which is to be fixed to the leader block 40. The pin head 13 is comprised of a cylinder shape and a corn shape attached at the tip of the threader pin 100. The leader block 40 has a recess 12 that receives therein the pin head 13. The leader block 40 has a lower portion thereof cut off at a position where the recess 12 is formed. In the case of FIG. 23, the pin head 13 can be securely fixed to the recess 12 of the leader block 40 as the cylinder shape of the pin head 13 provides a secure fit. Accordingly, appropriate threading is possible in the old magnetic-tape cartridge.
FIG. 24 is an illustrative drawing showing an example of the leader-block portion 20 or 22 of the new magnetic-tape cartridge shown in FIGS. 20C and 20D or FIGS. 21A and 21B.
In FIG. 24, the threader pin 100 connected to a tip of the threader arm 11 has the pin head 13 attached thereto which is to be fixed to a leader block 41. The pin head 13 is comprised of a cylinder shape and a corn shape attached at the tip of the threader pin 100. The leader block 41 has a recess 14 that receives therein the pin head 13. The leader block 41 has a lower portion thereof scraped off from an inner surface of the recess 14, and has a front side facing the view of FIG. 24 missing at a position where the recess 14 is provided. In the case of FIG. 24, therefore, the pin head 13 cannot be securely fixed to the recess 14 of the leader block 41. Accordingly, appropriate threading is impossible in the new magnetic-tape cartridge.
FIG. 25 is an illustrative drawing showing the leader-block portion 20xe2x80x2 of the old magnetic-tape cartridge of FIGS. 20A and 20B in a different arrangement.
In FIG. 25, a threader pin 101 connected to a tip of the threader arm 11 has a pin head 15 attached thereto which is to be fixed to the leader block 40. The pin head 15 is comprised of a corn shape and a cylinder shape attached to the corn shape toward the tip of the threader pin 101. The leader block 40 has the recess 12 that receives therein the pin head 15. The leader block 40 has a lower portion thereof cut off at a position where the recess 12 is formed. In the case of FIG. 25, therefore, the pin head 15 cannot be fixed to the recess 12 of the leader block 40. Accordingly, appropriate threading is not possible in the old magnetic-tape cartridge.
FIG. 26 is an illustrative drawing showing the leader-block portion 20 or 22 of the new magnetic-tape cartridge of FIGS. 20C and 20D or FIGS. 21A and 21B in a different arrangement.
In FIG. 26, the threader pin 101 connected to a tip of the threader arm 11 has the pin head 15 attached thereto which is to be fixed to the leader block 41. The pin head 15 is the same as the one shown in FIG. 25. The leader block 41 has the recess 14 that receives therein the pin head 15. The leader block 41 has a lower portion thereof scraped off from an inner surface of the recess 14, and has a front side facing the view of FIG. 26 missing at a position where the recess 14 is provided. In the case of FIG. 26, the pin head 15 can be securely fixed through secure contact between the lower inner surface of the recess 14 and the cylinder shape portion of the pin head 15. Accordingly, appropriate threading is possible in the new magnetic-tape cartridge.
In the manner as described above, it depends on a type of a magnetic-tape cartridge whether the recess of the leader block 4 can be securely fixed to the pin head. When a secure fix cannot be provided, the magnetic-tape cartridge cannot be threaded.
FIG. 27 is a chart showing a relation between speed of the leader block 4 at a time of threading and rotations of the threader motor 5.
In FIG. 27, the speed of the leader block 4 and the threader pin 10 is plotted on the vertical axis, and a distance that the leader block 4 covers from a start of a thread operation to an end of the thread operation is shown on the horizontal axis as the total number of revolutions of the supply-side reel (i.e., of the cartridge). This data is obtained by setting rotation of the threader motor to a fixed rate and setting the medium to a desired predetermined diameter. What is shown in FIG. 27 is data that is obtained during a threading operation between a time when the leader block 4 and the threader pin 10 start moving from the magnetic-tape cartridge and a time when the leader block 4 and the threader pin 10 reach inside the machine reel 3 past the three roller guides 6. As shown in FIG. 27, the speed exhibits a rapid increase after the number of revolutions becomes 150, and reaches its peak when the number of revolutions is about 180. This corresponds to a period when the threader pin 10 and the leader block 4 start moving from the magnetic-tape cartridge 2 to reach the first one of the roller guides 6. After this, the speed shows a rapid decrease until the number of revolutions becomes 225. Then, the speed goes up until the number of revolutions is around 255. At this point of time, the leader block 4 and the threader pin 10 have passed the first one of the roller guides 6 to reach the second one of the roller guides 6.
When the threader pin 10 and the leader block 4 hit one of the roller guides 6, the speed shows a rapid decrease, resulting volatile speed changes. This puts extra pressure on the magnetic tape, which may result in a damage on the magnetic tape when the tape is rather thin. Data on the magnetic tape may be permanently lost.
Further, the volatile speed changes create vibrations during the threading operation, causing tracking error when data recorded on the magnetic tape needs to be followed along a track thereof.
The same problems are observed during an unthreading operation when the magnetic tape is wound to be returned to the magnetic-tape cartridge.
As described above, different magnetic-tape cartridges have different recess shapes in the leader block portion, so that the head of the threader pin may not be securely fixed to the leader block, resulting a failure to engage in a threaded position.
Further, volatile speed change during a threading or unthreading operation creates extra tension applied to the magnetic tape, causing tape damages and data losses.
Moreover, volatile speed change during a threading or unthreading operation generates vibration, which shakes a head-seek mechanism or a tracking mechanism, possibly resulting in tracking error.
Accordingly, there is a need for a magnetic-tape device which can provide secure threading for different types of magnetic-tape cartridges, and can suppress damage on the magnetic tape.
Accordingly, it is a general object of the present invention to provide a magnetic-tape device which can satisfy the needs described above.
It is another and more specific object of the present invention to provide a magnetic-tape device which can provide secure threading for different types of magnetic-tape cartridges, and can suppress damage on the magnetic tape.
In order to achieve the above objects according to the present invention, a device for receiving a tape cartridge having a reel and a record tape winded around the reel where the record tape has a mounting unit attached to one end thereof includes an engaging unit which engages with the mounting unit, a threader arm which carries the engaging unit together with the mounting unit along a predetermined path to thread the record tape in the device during a threading operation and to unthread the record tape from the device during an unthreading operation, a reel motor which drives the reel of the tape cartridge, and a control unit which controls the reel motor to adjust tension in the record tape during the threading operation and the unthreading operation.
The device as described above controls the reel motor for driving the reel of the tape cartridge so as to control tension in the record tape. Thus, damage on the record tape can be avoided.
According to another aspect of the present invention, a device for receiving a tape cartridge having a record tape therein where the record tape has a mounting unit attached to one end thereof includes an engaging unit which engages with the mounting unit, and a threader arm which carries the engaging unit together with the mounting unit along a predetermined path to thread the record tape in the device, the engaging unit being configured to securely fit in the mounting unit for at least two different types of tape cartridges.
The device as described above has the engaging unit that is configured to securely fit in the mounting unit for at least two different types of tape cartridges. Therefore, the device can provide secure threading for different types of magnetic-tape cartridges.